Glass insulating panel

ABSTRACT

A glass panel includes a first glass substrate, a second glass substrate, a spacer profile at the periphery of the glass panel between the first and the second glass substrate. There is an intermediate substrate in the intermediate space between the first and the second glass substrates, the substrate having a first coefficient of thermal expansion, and means to maintain the intermediate substrate within the intermediate space. The panel also includes a second profile, having a second coefficient of thermal expansion, positioned facing the inner face of the spacer profile within the intermediate space between the first and second glass substrates of the glass panel. The second profile carries the means to maintain the intermediate substrate within the intermediate space. A difference between the first coefficient of thermal expansion and the second coefficient of thermal expansion is less than or equal to 20%.

FIELD OF THE INVENTION

This invention relates to glass panels, and to methods of manufacturing the same.

DESCRIPTION OF THE RELATED ART

Glass panels are used in multiple applications such as windows, doors, transparent walls, shelves, show cases for instance in a building and also in vehicles.

A certain type of glass panels that can be particularly interesting for its insulating properties are the multiple glass panels. Such panels comprise several sheet of glass separated by gas filled intermediate space, a spacer profile at the periphery of the glass panel being used to maintain the intermediate spaces between the sheets of glass and a seal (commonly made of butyl) being used to seal the intermediate spaces. The most common multiple glass panels being the double glass panels or double glazings.

Among the glass panels, for instance, the glass lighting panels with integrated light sources such as light emitting diodes (LEDs), are known, e. g. for displaying information, for decoration or for lighting purposes. For these application areas, the manufacturing of a glass panel with electronic components typically comprises the steps of depositing a conductive layer on a first glass substrate, realization of electronic circuits in the conductive layer and depositing of electronic components on the conductive layer, connected to the electronic circuits. In the case of a laminated glass panel, a plastics interlayer is then deposited on the conductive layer and a sandwich is obtained by the application of a second glass substrate on the plastics interlayer, which is then laminated as outlined before. In the case of an insulating glass panel, a second glass substrate is maintained, thanks to a spacer profile deposited at the periphery of the first glass substrate, at a distance from the first glass substrate so as to form an intermediate space between the first and second glass substrates.

In each of these applications it is necessary to furnish an electric supply to the conducting layer for supplying electrical power to the LEDs. EP 1 840 449 describes such a panels of glass embedding LEDs. The LEDs are arranged in a regular grid at 5 cm intervals such that the array of diodes covers substantially the entire area of glazing panel. Each LED has a surface area of about 4 mm². First and second bus bars extend substantially along the entire length of one edge of the panel between the two glass sheets.

It is also known to use light sources such as light emitting diodes (LEDs) that are arranged to emit light into laminated glass panels along a plane of the panel such as described in WO2010097110A1. In that document, the LEDs are arranged to emit light into the plastic interlayer that is at least partially light diffusive to cause the light to be deflected which causes the glass panel to be illuminated.

It is also known to use LEDs that are arranged to emit light into multiple glazings panels along a plane of the panel such as described in US20080184636A1.

Lighting panels comprising at least one organic glass layer with LEDs that are arranged to emit light into the organic glass layer such as Plexiglas EndLighten sold by EVONIK Industries are also known. In such panel, the organic glass layer is made of Poly(methyl methacrylate) embedding colorless diffuser particles which cause the light to diffuse forwards.

Most of the time, the periphery of the glass panels are embedded in a frame that is used to hide the periphery of the panel (comprising for instance the spacer profile and the seal) but also to attach the glass panel to the part of the building or structure that shall receive it.

The fixation of the frame to the building or structure can be done for example thanks a seal (mortar) material that fills the space between the frame and the surfaces of an opening in which the panel should be integrated or thanks to screws, thanks to glues, Nevertheless, when a panel comprising multiple sheets of glass (organic and/or inorganic) and/or plastics and/or other materials is fixed in a vertical position depending of the material (and more particularly for more flexible materials), the sheet has to have a minimum width (for example 8 mm for a sheet of Plexiglas EndLighten of 1 m×1 m dimensions) in order to avoid buckling. This can be a concern in particular when the weight or the cost (that is closely related to the width of the substrate) of the panel needs to be reduced.

SUMMARY OF THE INVENTION

According to a first aspect, the invention provides a glass panel, comprising:

-   -   a first glass substrate,     -   a second glass substrate,     -   a spacer profile at the periphery of the glass panel between the         first and the second glass substrate, the spacer being used to         maintain an intermediate space between the first and second         glass substrates, the spacer profile having an outer surface and         an inner surface,     -   an intermediate substrate in the intermediate space between the         first and the second glass substrates,     -   means to maintain the intermediate substrate within the         intermediate space.

According to present invention, the panel comprises further a second profile (100), having a second coefficient of thermal expansion, positioned facing the inner face of the spacer profile (103) within the intermediate space (104) between the first (101) and second (102) glass substrates of the glass panel (1), the said second profile (100) carrying on the means (108) to maintain the intermediate substrate (105) within the intermediate space (104), and wherein the difference between the first coefficient of thermal expansion of the intermediate substrate (105) and the second coefficient of thermal expansion of the second profile (100) is lower or equal to 20%.

Using a second profile to maintain the intermediate substrate within the intermediate space, the second profile having the same coefficient of thermal expansion than the coefficient of thermal expansion of the intermediate substrate allows to reduce the stress between the second profile and the intermediate substrate in the intermediate space between the first and the second glass substrates.

Embodiments of the invention can have any other features added, some such additional features are set out in dependent claims and described in more detail below.

According to an aspect of the invention, the panel is disposed in a vertical position and the means to suspend the intermediate substrate comprises means to attach a upper portion of the intermediate substrate to a upper portion of the second profile.

Therefore, thanks to the fact that the intermediate substrate may be suspended in the intermediate space, when the panel is arranged in the vertical position, buckling of the intermediate substrate is prevented whatever the width of the intermediate substrate. Then, smaller width intermediate substrate can be used in order to reduce the weight or cost of the panel.

It is understood in the present invention that the term “outer surface of the spacer profile” means the surface in contact with the environment outside the glass panel and the term “inner surface of the spacer profile” means the surface in contact with the intermediate space between the first and second glass substrates of the glass panel.

To avoid any doubt, the term “coefficient of thermal expansion” and its abbreviation “CTE” will be used equally in the present invention.

According to the present invention, said second profile comprises means to maintain the intermediate substrate in the intermediate space between the first and the second glass substrates.

According to an embodiment of the present invention, said attachment means consist in:

-   -   at least one first opening in said upper portion of the second         profile,     -   at least one second opening in the lower portion of the second         profile, the first and the second openings being disposed in         regard,     -   the at least first and second opening being designed to lodge at         least a portion of the edges of the intermediate substrate.

According to a preferred embodiment of the present invention, the intermediate substrate is preferably fixed to the internal faces of the first and second openings provided in the second spacer profile.

According to a preferred embodiment of the present invention, at least a portion of the edges (upper and lower) of the intermediate substrate of the intermediate substrate inserted into corresponding first and second openings are glued to the internal faces of the first and second openings provided in the second spacer profile in order to well fix the intermediate substrate to the second pacer profile to avoid any movement of the intermediate substrate.

According to an aspect of the invention, the intermediate substrate is an intermediate organic glass substrate.

According to an aspect of the invention, the panel comprises at least one light source.

According to an aspect of the invention, the second profile comprises means to lodge the at least one light source so as the at least one light source emits light into the intermediate organic glass substrate predominantly along a plane of the panel.

According to an aspect of the invention, at least part of the intermediate organic glass substrate is arranged to deflect the light out of the plane of the panel and through at least one of the first and second glass substrates to provide a diffused light output.

By using a second profile to suspend the intermediate substrate within the intermediate space having the same coefficient of thermal expansion than the coefficient of thermal expansion of the intermediate substrate and at least one light source to emit light into the intermediate organic glass substrate allows:

-   -   to reduce the stress between the second profile and the an         intermediate substrate in the intermediate space between the         first and the second glass substrates,     -   to maintain a set distance between the at least one light source         and intermediate substrate.

Thus, a glass panel with an improved esthetic with a better diffusion of the light emitted form at least one light source and lifetime is proposed by the present invention.

Also, by having the light deflected by the organic glass substrate, it can be spread or diffused more widely to reduce problems caused by more direct illumination from point sources.

By having the intermediate organic glass substrate arranged between a first and a second glass substrates, the organic glass substrate is then protected against any risk of the occurrence of defects such as scratches and/or stripes on its surface. And then local refraction of the light beam propagating through defects in the panel are avoided. Then, the uniformity of the light generated at the surface of panel and the overall aesthetics of the illuminated panel are improved or are kept.

In the following, the expression default encompasses all kind of surface default such as scratches, stripes, protrusion, roughness, striates, projections, slits, puncture, groove, depression, . . . . The defects can be microscopic. The defects can be macroscopic.

According to another aspect of the invention, the spacer profile and/or the second profile also comprises means to dissipate heat generated by the at least one light source.

According to another aspect of the invention, the means to dissipate heat comprise a heat sink embedded in the spacer.

Then, by having means to dissipate heat embedded in the spacer, the invention allows for a better dissipation of heat generated by the light source(s) and then allows to embed in the panel higher densities of light sources and/or higher power light source(s). As a matter of fact, for a good and efficient functioning of most of the light sources (such as LEDs for instance), temperature in the environment around the light sources shall be controlled to be inferior to a temperature threshold (above which the light source intensity or efficiency starts to decrease). Most of the light sources generate heat when functioning due to their electric powering. The higher the electrical power supplied to the light source, the more heat is generated. Moreover, the higher the density of light sources in an environment, the more heat is generated in that environment. As a matter of fact, preliminary tests have shown that, in such glass lighting panel where the light sources are LEDs, the ambient temperature of the LEDs can be up to 60° C., which greatly reduces their lifetime. Therefore, the heat dissipating means are very important particularly when high light output is required.

A solution to limit/avoid the temperature increase due to electrical powering of the light sources is to dissipate generated heat.

According to another aspect of the invention, the means to lodge at least one light source is a profile embedded into the second profile between the first and the second glass substrates so as to face an edge of the intermediate organic glass substrate.

According to another aspect of the invention, the profile embedded in the second profile to lodge at least one light source has a inversed U-shape and the at least one light source is placed on the profile to face an edge of the intermediate organic glass substrate. Preferably, the profile is a metallic profile and more preferably the profile is an aluminum profile.

According to another aspect of the invention, the intermediate organic glass substrate is at least partially light diffusive to cause the light to be deflected.

According to another aspect of the invention, the intermediate organic glass substrate is a Poly(methyl methacrylate) layer.

According to another aspect of the invention, the intermediate organic glass substrate is a Poly(methyl methacrylate) layer embedding colorless diffuser particles which cause the light to diffuse forwards.

Another aspect provides a second profile positioned facing the inner face of the spacer profile within the intermediate space between the first and second glass substrates of the glass lighting panel, comprising:

-   -   means to maintain an intermediate substrate in the intermediate         space between the first and the second glass substrates and     -   means to lodge at least one light source so as the at least one         light source is arranged to emit light into the intermediate         substrate predominantly along a plane of the panel.

According to another aspect of the invention, the second profile may also comprises means to dissipate heat.

According to another aspect of the invention, the means to dissipate heat comprise a heat sink embedded in the profile.

Another aspect provides a method of manufacturing a glass lighting panel comprising a first glass substrate and a second glass substrate, comprising the following step:

-   -   providing a spacer profile at the periphery of the glass panel         between the first and the second glass substrate to maintain an         intermediate space between the first and second glass         substrates, the spacer profile having an outer and an inner         surfaces.

According to an aspect of the invention, the method also comprises the following steps:

-   -   maintaining, thanks to a second profile, an intermediate organic         glass substrate in the intermediate space between the first and         the second glass substrates, the difference of CTE between the         CTE of the intermediate organic glass substrate and the CTE of         the second profile is lower or equal to 20%,     -   lodging, thanks to the second profile, at least one light source         so as the at least one light source emits light into the         intermediate organic glass substrate predominantly along a plane         of the panel,     -   arranging at least part of the intermediate organic glass         substrate to deflect the light out of the plane of the panel and         through at least one of the first and second glass substrates to         provide a diffused light output.

Any of the additional features can be combined together and combined with any of the aspects. Other advantages will be apparent to those skilled in the art, especially over other prior art. Numerous variations and modifications can be made without departing from the claims of the present invention. Therefore, it should be clearly understood that the form of the present invention is illustrative only and is not intended to limit the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

How the present invention may be put into effect will now be described by way of example with reference to the appended drawings, in which:

FIG. 1 shows a cross section view a portion of a panel according to a particular embodiment according to which the light sources are LEDs that are arranged at the periphery of the glass panel in the second profile in order to emit light in a direction along the plane of the glass substrates.

FIG. 2 illustrates the main steps of a method of manufacturing of the glass lighting panel of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other orientations than described or illustrated herein.

Similarly it should be appreciated that in the description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

The invention will now be described by a detailed description of several embodiments of the invention. It is clear that other embodiments of the invention can be configured according to the knowledge of persons skilled in the art without departing from the technical teaching of the invention, the invention being limited only by the terms of the appended claims.

Some of the features described below arise from an appreciation that panel comprising at least two sheets of glass embedding an intermediate substrate e.g. made of inorganic glass and/or plastics and/or other materials is fixed in a vertical position depending of the material (and more particularly for more flexible materials), the intermediate substrate has to have a minimum width in order to avoid buckling. This can be a concern in particular when the weight of the panel needs to be reduced.

Thus an objective of at least some of the embodiments is to provide a panel of glass comprising an intermediate substrate in which the intermediate substrate can have any and all widths without buckling of the intermediate substrate.

Thus an objective of at least some of the embodiments is to provide a panel of glass comprising an intermediate substrate the weight of which can be reduced.

Some other of the features described below arise from an appreciation that the surfaces of an organic glass substrate are highly sensitive to defects such as scratches and/or stripes and/or protrusions and then, if default are present on the surface of such a substrate, light generated on the surface of such a substrate is not perfectly uniform and the overall aesthetics of the panel is decreased.

Thus an objective of at least some of the embodiments is to provide a panel of glass including at least one light source which provides surface lighting with an improved uniformity. Another objective of some embodiments is to provide such a surface lighting panel in which the aesthetics of the panel is improved. Another objective of at least some embodiments is to provide such a surface lighting panel which allows to embed in the panel higher densities of light sources and/or higher power light source(s).

Some embodiments involve a glass lighting panel, comprising a first glass substrate, an intermediate organic glass substrate, having a first coefficient of thermal expansion, a second glass substrate, a spacer profile at the periphery of the glass panel between the first and the second glass substrates, and a second profile being used to maintain an intermediate space between the first and the second glass substrate, having a second CTE, the difference between the first of the intermediate organic glass substrate and the second CTE of the second profile is lower or equal to 20%. The glass substrates can encompass glass equivalents such as hard plastic or Perspex acrylic or polycarbonate materials. The panel can have at least one light source lodged in the second profile so as to emit light into the intermediate organic glass substrate predominantly along a plane of the panel.

The organic glass layer can be arranged to be at least partially light diffusive such that light emitted by the at least one light source is deflected out of the plane of the panel and through the surfaces of at least one of the glass substrates. This can be made partially diffusive by choice of properties of the material, by adding particles (e.g. colorless or colored diffuser particles), by adding any kind of reflective or partially reflective structures, or by surface treatments to hinder total internal reflection and so on. The panel according to the invention can be flat and be for instance a building window or door, a partition wall for indoor or outdoor architectural applications, a display panel (e.g. for advertising), a road sign, . . .

Nevertheless, the panel does not need to be flat, it can be formed to have a curved main surface for instance, the panel can be a vehicle glazing.

Some additional features of some of the embodiments are as follows.

In some cases at least one light source such as an LED, OLED etc. can be embedded in the second profile (in lodging means of the second profile) provided between the spacer profile and the intermediate space between the first and the second panes of glass, in order to emit light into the intermediate organic glass substrate (preferentially at the edge of the intermediate organic glass substrate) in a direction predominantly included in the plane of the panel.

According to a first aspect of the invention, only one light source can be lodged in the second profile in order to emit light into the intermediate organic glass substrate. It can be lodged everywhere in the second profile and emit light in every portion of the edges of the intermediate organic glass substrate.

According to a preferred aspect of the present invention, the at least one light source is provided on a profile embedded into the second profile/

Clearly according to other aspects of the invention, two, three, four, or any other quantity of light sources can be lodged everywhere in the second profile having the same CTE than the intermediate organic glass substrate so as to emit light into the intermediate organic glass substrate. In case of a perpendicular panel comprising a perpendicular intermediate organic glass substrate comprising four edges, the light sources can be lodged in the second profile so as to emit in any portion of any edge of the intermediate organic glass substrate. The light sources can also be lodged in the spacer on a regular basis so as to emit light on a regular basis in the four edges of the intermediate organic glass substrate.

Any kind of light source that can be embedded in the second profile having the same CTE than the intermediate organic glass substrate can be implemented in the present invention such as LED, OLED, laser diodes, fluorescent tube, fluorescent lamp, . . . .

According to the present invention, an opening is provided in the second profile in the place where the at least one light source is disposed in order to allow the light emitted from the at least one light source to be diffused into the intermediate organic substrate.

FIG. 1 shows a portion of a cross section view of a glass lighting panel 1 according to a particular embodiment of the invention.

The glass lighting panel 1 comprises a first glass plate or substrate (or sheet) 101, an intermediate substrate 105 that is for example an intermediate organic glass substrate 105 having a first CTE, a second glass plate or substrate (or sheet) 102, a plurality of LEDs 106, a spacer profile 103 at the periphery of the glass panel 1 between the first 101 and the second 102 glass substrates to maintain the intermediate space 104 (or cavity) between the first and the second glass substrates, and a second profile 100 having a second CTE, the difference between the first and the second CTE is lower or equal to 20%, the second profile 100 being used to maintain the intermediate substrate 105 in the intermediate space 104 (or cavity) between the first and the second glass substrates.

Preferentially, the second profile 100 comprises

-   -   means 107 to maintain the intermediate organic glass substrate         105 in the intermediate space 104, and     -   means 108 to lodge the LEDs 106 so that they emit light into the         intermediate organic glass substrate 105 predominantly along a         plane of the panel.

Preferentially, the means 108 to maintain the intermediate organic glass substrate 105 in the intermediate space 104 is an opening 1071 extending along at least a portion of the length of the intermediate organic glass substrate 105, the opening being arranged to lodge at least a bottom portion 1051 of the edges of the intermediate organic glass substrate 105.

More preferably, the means 108 to maintain the intermediate organic glass substrate 105 in the intermediate space 104 further comprises an opening 1072 extending along at least a portion of the length of the intermediate organic glass substrate 105, the opening being arranged to lodge at least a upper portion 1052 of the edges of the intermediate organic glass substrate 105, the first and the second openings 1071, 1072 being disposed in regard.

Preferentially, the means 108 is a metallic inversed U-shape profile embedded into the second profile 100 on which LEDs 106, (potentially in a housing for each LED 106) are arranged so as to face an edge 1051 of the intermediate organic glass substrate 105.

Preferably the second profile 100 can be made from any suitable material such as plastic or other material provided that the second profile 100 has the same CTE than the intermediate organic glass substrate 105.

The second profile 100 can be made from the same material or a different material than the intermediate organic glass substrate 105 provided that they have the same CTE.

The spacer profile 103 can be made from any suitable material such as alumina, stainless steel, plastic, and many other materials.

According to the present invention, the spacer profile 103 also comprises means to dissipate heat generated by the LEDs 106. Preferentially, the means to dissipate heat comprise a heat sink embedded in the spacer (not shown). Preferentially, the spacer profile is made from a heat conducting material such as a metal (e.g. alumina, stainless steel, . . . or combination thereof) or and the heat sink is made by realizing wings on the edge of the spacer profile 103 that is in contact with the external atmosphere (external edge of the spacer).

Preferentially, the panel comprises means to maintain the intermediate inorganic glass substrate 105 within the intermediate space 104.

Preferentially, the panel is disposed in a vertical position (for example it is the case when the panel is used as a window, or a door, or a separation wall or a vertical part of a show case, . . . ) and the means to suspend the intermediate inorganic glass substrate 105 comprises means to attach a upper portion 1052 of the intermediate substrate 105 to a portion 1032 of the second profile 100.

For instance, if the intermediate inorganic glass substrate 105 is rectangular and therefore comprises an upper 1052, two lateral edges 1051 and a bottom portion 1051.

Preferentially, the intermediate organic substrate 105 is fixed to the opening 1071 thanks to any suitable piece (such as a thanks to two nuts that are screwed to both threaded parts of the stem that exceed from both said first and second wings) or more preferably a material such as glue or is inserted under pressure (or pressed) in the opening.

Preferentially, at the level of the two lateral parts and a bottom part of the spacer profile 103, the means 107 to maintain the intermediate substrate 105 in the intermediate space 104 are just used to guide the intermediate substrate 105 and let a certain degree of liberty in all the directions. It can be obtained by choosing a spacing between the first and the second glass plates 101 102 that is higher than the width of the second profile 100.

On FIG. 1, the second profile is represented as having a rectangular section, obviously, for better heat dissipation performances, the spacer can have a more bulky rectangular section. A metallic profile reversed U-shape profile 108 is embedded in the second profile 100. The LEDs 106 are placed on the base of the U-profile 111 facing the intermediate organic substrate 105.

The metallic profile 108 allows particularly to bring near the at least one source of light 106 to the intermediate organic substrate 105 and to support also the at least one source of light 106.

According to the present particular embodiment, each LED 106 is lodged in a housing 108 of the spacer profile on a regular basis so as to emit light on a regular basis in the four edges of the intermediate organic glass substrate 105. For instance, the LEDs 106 are provided as a flexible adhesive strip, for instance, a LED strip sold by OSRAM with the reference LF06P-W4F-854 or VISTAR VFS-N3528-120W-L1, in order to be glued (e.g. with an adhesive tape) in the housing 108 of the second profile 102 and more particularly on the means 108. The means 108 is more preferably a metallic profile with a inversed U-shape.

According to the present particular embodiment, the glass lighting panel 1 is an rectangular insulating multiple glazing panel embedding a rectangular intermediate organic glass substrate. The intermediate space or cavity 104 can be filled with a gas such as air or any insulating gas, e.g. Argon, Krypton, Xenon, SF6, CO2, . . . or any combination of the previously mentioned gas. A sealant, e.g. a butyl coating, can be provided between the spacer and the internal surface (surface of the substrate that is in contact with the intermediate space 104) of the first and second glass substrate to seal the panel and avoid the gas to leave the cavity 104. Alternatively, a vacuum can be created in the intermediate space or cavity 104. Preferentially, the spacer profile 103 is filled with or contain desiccant to remove moisture trapped in the gas space during manufacturing of the panel 1.

In order to supply power to the LEDs, for instance, a hole is drilled in the edge of the spacer profile 103 and the second profile 102 through the means 108 and a cable is inserted through a protective tubular shaped polymer material. This tube protects the cable from the edges of the drilled (sharp) alumina. The cable is then soldered on adequate connection pad(s) of the flexible adhesive LED strip.

At least part of the intermediate organic glass substrate 105 is arranged to deflect the light out of the plane of the panel and through at least one of the first and second glass substrates to provide a diffused light output. Preferentially, it is at least partially light diffusive to cause the light to be deflected.

For instance, the organic glass substrate is a Poly(methyl methacrylate) layer and more particularly a Poly(methyl methacrylate) (hereafter referenced PMMA) layer embedding colorless diffuser particles which cause the light to diffuse forwards. For instance, the organic glass substrate has a width that is comprised between 2 mm to 10 mm or even lower. Such thin organic glass substrates can be used due to the fact that said substrate is maintained and potentially suspended and then no buckling occurs. For instance, the organic glass layer is a layer of Plexiglas Endlighten T, Grade number 0N001, 8 mm thickness that is sold by the company EVONIK Industries. The refractive index of this PMMA is 1.491 measured using ISO 489. According to another embodiment, the organic glass layer embeds particles only on a part of its volume, for instance only in a central part of that substrate. The CTE of the PMMA is comprised between 70 and 77.10⁻6/K⁻¹ Different particle concentrations can be used and can be adapted to the dimensions of the glass panel 1.

In case the intermediate organic glass substrate 105 is PMMA, the second profile is preferably made from PMMA material in order to have the same CTE.

The glass of the first and second glass substrates can be coated, tinted, tempered or bended or a combination of these.

Then, thanks to the presence of the diffuser particles in the intermediate organic glass substrate 105, the organic glass substrate 105 cause the light emitted by the light sources (LEDs 106) to diffuse forward and then deflects the light emitted by the LEDs 106 out of the plane of the panel 1 and through the first and second glass substrates to provide a diffused light output.

Basic methods for assembling/manufacturing glass, without the novel features of the present invention, for use in this and other embodiments are well-known in the window/double glazing industry.

According to a present particular embodiment, a method of manufacturing of the glass lighting panel 1 comprising the first glass substrate 101 and the second glass substrate 102, is illustrated on FIG. 2 and comprises the following steps:

-   -   providing 301 the spacer profile 103 at the periphery of the         glass panel between the first and the second glass substrate to         maintain the intermediate space 104 between the first and second         glass substrates,     -   providing 302 the second profile 100 positioned facing the inner         face of the spacer profile 103 within the intermediate space         between the first 101 and second 102 glass substrates of the         glass panel, the second spacer having the same coefficient of         thermal expansion than the coefficient of thermal expansion of         the intermediate substrate,     -   maintaining 303, thanks to the second profile, an intermediate         organic glass substrate 105 in the intermediate space between         the first and the second glass substrates,     -   lodging 304, thanks to the second profile, the LEDs 106 so as         they emit light into the intermediate organic glass substrate         predominantly along a plane of the panel,     -   arranging 305 at least part of the intermediate organic glass         substrate 105 to deflect the light out of the plane of the panel         and through at least one of the first and second glass         substrates to provide a diffused light output.

In some cases one or both the first and second glass substrates can be flat soda lime glass, notably float glass. One or both of the first and second glass substrates may be clear glass, extra clear glass or body tinted glass. Particularly when intended for use in window applications, the glazing panel may be substantially transparent. In this case, it may have a light transmission (CIE Illuminant C) of greater than or equal to 40%, 50%, 60% or 70% and/or a level of haze of less than or equally to 5%, 3% or 2% for example. Particularly when intended for decoration and/or lighting purposes, it may be unnecessary and/or undesired for the panel to be substantially transparent. In this case, it may have a light transmission (CIE Illuminant C) of less than or equal to 20%, 10%, or 5% and/or a level of haze of greater than or equally to 30%, 40% or 50%.

Examples of additives to make the organic glass layer diffusive can encompass inorganic particles of glass, silica, mica, synthetic mica, calcium carbonate, barium sulfate, talc, montmorillonite, kaolin clay, bentonite, hectorite, etc., metal oxide particles of titanium oxide, zinc oxide, tin oxide, alumina, etc., or organic polymer particles of acrylic beads, styrene beads, benzoguanamine, silicone, etc.

More diffusion can be obtained by surface roughening of a light-emitting face accomplished by cutting using a saw or an automatic cutter (for example, an NC router) or by blasting, surface grinding using a grinder, emboss forming, etc. In the case of blasting, particles are applied using a high-speed blasting machine over the surface of the organic glass layer, the interlayers or the glass substrates to form random projections and depressions, and the thus formed surface can be used as the light-emitting face. In the case of grinding, a grinder using, for example, a file is used to grind the surface.

The light sources can be colored, and optionally arranged so that there is color mixing to achieve a uniform white. The relative levels of the colors can be controlled to control the color temperature if desired. The light sources can also emit in the ultraviolet or infrared spectrum. The panels can be incorporated into buildings, windows, mirrors, backlights for display systems and so on. Arrays of the panels can be built up to illuminate larger areas.

Other variations can be envisaged within the scope of the claims. 

The invention claimed is:
 1. A glass panel, comprising: a first glass substrate; a second glass substrate; a spacer profile at a periphery of the glass panel between the first and the second glass substrate, the spacer being used to maintain an intermediate space between the first and second glass substrates, the spacer profile having an outer surface and an inner surface; an intermediate substrate in the intermediate space between the first and the second glass substrates, having a first coefficient of thermal expansion; means to maintain the intermediate substrate within the intermediate space; a second profile, having a second coefficient of thermal expansion, positioned facing the inner surface of the spacer profile within the intermediate space between the first and second glass substrates of the glass panel, wherein the second profile carries the means to maintain the intermediate substrate within the intermediate space, and wherein a difference between the first coefficient of thermal expansion of the intermediate substrate and the second coefficient of thermal expansion of the second profile is less than or equal to 20%.
 2. The glass panel according to claim 1, wherein the means to maintain the intermediate substrate within the intermediate space comprises: at least one first opening in an upper portion of the second profile, at least one second opening in a lower portion of the second profile, the first and the second openings being disposed in regard, the at least first and second openings being designed to lodge at least a portion of edges of the intermediate substrate.
 3. The glass panel according to claim 1, wherein the panel is disposed in a vertical position and the means to maintain the intermediate substrate comprises means to attach an upper portion of the intermediate substrate to an upper portion of the second profile and/or to attach a bottom portion of the intermediate substrate to a bottom portion of the second profile.
 4. The glass panel of claim 1, wherein the intermediate substrate is preferably fixed to the internal faces of the first and second openings provided in the second spacer profile.
 5. The glass panel of claim 2, wherein the at least a portion of the edges (upper and lower) of the intermediate substrate is inserted into corresponding first and second openings and glued to internal faces of the first and second openings.
 6. The glass panel of claim 1, wherein the second spacer has a same coefficient of thermal expansion as the intermediate substrate.
 7. The glass panel of claim 1, wherein the second profile and the intermediate substrate are made of Poly(methyl methacrylate) material.
 8. A lighting panel comprising the glass panel of claim 1, further comprising: at least one light source, wherein the intermediate substrate is an intermediate organic glass substrate, wherein the second profile further comprises means to lodge the at least one light source so as the at least one light source emits light into the intermediate organic glass substrate predominantly along a plane of the panel, and in that at least part of the intermediate organic glass substrate is arranged to deflect the light out of the plane of the lighting panel and through at least one of the first and second glass substrates to provide a diffused light output.
 9. The lighting panel of claim 8, wherein the means to lodge at least one light source is a profile embedded into the second profile between the first and the second glass substrates so as to face an edge of the intermediate organic glass substrate.
 10. The lighting panel of claim 8, wherein the means to maintain the intermediate substrate within the intermediate space has a inversed U-shape profile and is made from a metallic material.
 11. The lighting panel of claim 8, wherein the means comprises at least a housing being arranged between the first and the second openings so as to face an edge of the intermediate organic glass substrate.
 12. The lighting panel of claim 8, wherein the intermediate organic glass substrate is at least partially light diffusive to cause the light to be deflected.
 13. The lighting panel of claim 8, wherein the intermediate organic glass substrate is a Poly(methyl methacrylate) layer.
 14. The lighting panel of claim 13, wherein the intermediate organic glass substrate is a Poly(methyl methacrylate) layer embedding colorless diffuser particles which cause the light to diffuse forwards.
 15. The lighting panel of claim 14, wherein the intermediate organic glass substrate and the second profile are made of Poly(methyl methacrylate) material.
 16. A glass panel, comprising: a first glass substrate; a second glass substrate; a spacer profile at a periphery of the glass panel between the first and the second glass substrate, the spacer being used to maintain an intermediate space between the first and second glass substrates, the spacer profile having an outer surface and an inner surface; an intermediate substrate in the intermediate space between the first and the second glass substrates, having a first coefficient of thermal expansion; means to maintain the intermediate substrate within the intermediate space; a second profile, having a second coefficient of thermal expansion, positioned facing the inner surface of the spacer profile within the intermediate space between the first and second glass substrates of the glass panel, wherein the second profile carries the means to maintain the intermediate substrate within the intermediate space by defining a cavity configured to receive the intermediate substrate, and wherein a difference between the first coefficient of thermal expansion of the intermediate substrate and the second coefficient of thermal expansion of the second profile is less than or equal to 20%.
 17. The glass panel according to claim 16, wherein the panel is disposed in a vertical position and the means to maintain the intermediate substrate comprises means to attach an upper portion of the intermediate substrate to an upper portion of the second profile and/or to attach a bottom portion of the intermediate substrate to a bottom portion of the second profile.
 18. The glass panel of claim 17, wherein the second profile maintains the intermediate substrate within the cavity such that the upper portion of the second profile touches an edge and two lateral edges of the upper portion of the intermediate substrate and/or the bottom portion of the second profile touches an edge and two lateral edges of the bottom portion of the intermediate substrate. 